Does one need a thermostat AND a rheostat?

I read on another thread that a rheostat is not really necessary, but then was just advised to get both. I'm not at all trying to disregard that advice, but I want to be clear before I head off with my credit card in hand.

A thermostat adjusts the temp to the desired temp, but a rheostat does not, correct? It simply cranks the heat up or down? Wouldn't a thermostat do the same thing? Are both necessary? I use a probe to check the temps, by the way. Can anyone clarify this for me? Thanks.

Oh nevermind. I saw that Nanci suggested a thermostat OR rheostat. Sorry!

The rheostat changes the temp by changing the supplied power to the device. (Think of a lamp dimmer). So you need to adjust it seasonally.

There are two types of thermostats: on/off and proportional. The on/off type turns the power supply to the UTH off when it reaches the temp you set. However, the device may still continue to heat up a bit. The on/off type has a wider temp range- I'd say about 3-5 degrees higher and lower than what you set. Which isn't a bad thing for a cornsnake, as long as you know what the max temp it reaches is, by measuring it with a probed thermometer right on top of the glass over the heat matt.

A proportional thermostat allows you to digitally choose a temp, and then it supplies more power to the UTH as it is heating up, and less power as it reaches the set point, reducing the amount the UTH goes over the set temp to as little as .5F. So if you are picky and just want the temp to stay where you set it and not bounce all over the place you may be happier with a proportional thermostat, which is going to start at about $100.

It took me about a year or more to get to the stage that I just wanted the temps to be what I set. I started out with Flukers thermometers that I just set on the heat mat and checked periodically. Then I got Big Apple Herp probed thermometers, which I mounted on the wall in plain sight so I always knew what the temp was and got to see how much it varied. Then I gradually switched everyone over to proportional thermostats.

Some highly respected breeders do not recommend using a thermostat at all and (paraphrasing) say that a deep (3-4") layer of aspen will allow the snake to find the proper temp without burning itself. They may be in the minority, but it works for them and I am not one to say a huge cornsnake breeder is wrong. I'm just more comfortable with a thermostat and a UTH that is not reaching 120F.

Thanks, Nanci..that helps a lot. Unfortunately, I just got back from three stores, and none had what I wanted. I found a heat mat, but it's definitely not large enough. The others they had were way too large. No thermostats at all to choose from, so I took their last rheostat. The reptile store is about a half hour away, but the boys were hungry, so hopefully later today they'll be up for another errand.

By the way, is it possible to buy thermostats at a Home Depot type of store, or are the ones you're suggesting only used for the heat mats?

This is a popular inexpensive thermostat. I found it by googling for $22.95. I usually look on eBay and find the lowest price combined with shipping.

http://tinyurl.com/5ztytu

This is a nice step up on/off thermostat for $40:

http://tinyurl.com/2ggzzd

My favorite thermometer:

http://tinyurl.com/yqd3xt

Expensive thermostat that I love:

http://spyderrobotics.com/products/herpstatnd.html

I think Home Depot only sells house thermostats.

If you can't find a thermostat today, you can see how the rheostat works for you- plenty of people do fine with them, but if you have big temp changes in your home, the rheostat doesn't adjust itself to compensate, you have to keep adjusting it.

Ebay is great, though I only use the UK one. I got my thermostat off there, its alot cheeper than my local shops

Nanci, thanks so much for those links! We actually have huge temperature fluctuations in our home, especially in the evenings. My husband smokes, so after the kids go to bed, he turns on the central exhaust fan and opens the windows, which turns the downstairs into a wind tunnel. The temp drops about 8-12 degrees within ten minutes. I'll definitely check out those thermostats. Thanks tons!

Be careful with the rheostats sold specifically for reptiles. The ZooMed model is well known for not being able to dial the temp down low enough for corn snakes.

For a rheostat I prefer either a pre made lamp dimmer from WalMart or building my own , using the instructions in a large thread on this forum.

The only time I would use BOTH would be for a setup with 2 heat mats where you want one lower than the other, such as for a ball python. Plug the rheostat into the thermostat and one heat mat in the thermostat aand the other on the rheostat. You can then use the rheostat to lower the temp on one of the mats while the thermostat controls the warmer one.